Mem. Amer. Acad. Arts, n. s. 4: 93. 1849.
Subshrubs or shrubs, 10–40[–80] cm (evergreen). Stems erect, strictly branched. Leaves cauline; mostly alternate [opposite]; blades simple [pinnate], linear to clavate or acerose (± fleshy), margins entire, faces usually glabrous, sometimes puberulent (oil-glands marginal or submarginal). Heads radiate, borne singly. Calyculi 0. Involucres turbinate to hemispheric, 3.5–5[–8] mm diam. Phyllaries persistent, 8–14 in ± 2 series (distinct to bases, linear to lance-linear [ovate], carinate, each usually bearing 1–5 oil-glands). Receptacles convex to hemispheric, ± pitted, rarely paleate (paleae readily falling). Ray florets 8(–13), pistillate, fertile; corollas bright yellow. Disc florets 15–70, bisexual, fertile; corollas yellow to orange, tubes much shorter than cylindro-funnelform throats, lobes 5, lance-deltate. Cypselae cylindric to fusiform, strigillose or glabrescent; pappi persistent, of [20–]30–40 bristles in ± 1 series. x = 15.
sw United States, Mexico.
Species 5 (1 in the flora).